A high voltage overhead transmission line is apt to be influenced by meteorological environment (such as gale, ice and snow, etc.) and human factor and thus fails to function, thereby resulting in a damage to the equipment on the power transmission line, and influencing safe operation of the power transmission line, even severely coming to a standstill of power supply in a large area, which causes heavy losses to national economy. For example, a breeze vibration and a lead wind yaw caused by breeze are hidden troubles commonly found on the high voltage overhead line, which is the main reason of fatigue and broken strand of the high voltage overhead transmission line. The galloping of the line formed under a strong wind condition generally lasts for up to several hours, which will bring a huge destructive effect on the high voltage power transmission line. When experiencing rain and snow, the line is covered with ice, and the pulling wires of poles or towers are more likely to be frozen. The freezing on symmetric pulling wires is not balanced in most cases, which will result in an inclination of the tower or pole. This is also a huge hidden trouble on security assurance of the power transmission line.
Trouble phenomenon of the power transmission line such as breeze vibration, galloping, icing, windage yaw, dirt, lightening strike is mostly caused by the influence of local hostile meteorological environment. Our country has a vast territory, and the power transmission line has features such as the great dispersibility of dangerous points, the long distance and difficulty in monitoring and maintenance. Monitoring records provided at regular times and fixed points in a certain region by observatory are unable to reflect meteorological condition of specific power transmission line corridor completely and correctly. In addition, in case of absence of the historical meteorological data of the power transmission line corridor, there may be certain difficulties in judging, preventing and researching the breakdown of the power transmission line.
Around the Spring Festival of 2005, an extremely rare weather of freezing rain and rain and snow appears in central region of China. Especially two provinces of Hunan and Hubei are respectively suffered from a natural disaster in which the power transmission line is covered with ice in a large area, a long duration and a high intensity in 50 years. It results in equipment failures in 500 KV transformer substation of the Central China Power Grid 5 times, and tripping operations on 18 power transmission lines of 500 KV AC/DC 69 times. In January, 2008, a dozen provinces and cities in southern part of the whole country encountered a rare weather of ice and snow, and power failure and accidents appeared in a large area since the power transmission line is covered with ice, which brings an extremely serious adverse effect on people living and the society. Power facilities in regions of Hubei, Hunan, Henan, Jiangxi, Sichuan, Chongqing, Zhejiang, Anhui, Fujian, Jiangsu, etc. have suffered from a great loss. It resulted in that 36740 power lines of more than or equal to 10 KV and 2016 transformer substations of more than or equal to 35 KV were stopped, and that 310321 towers or poles of more than or equal to 10 KV were collapsed and damaged, among which there were 8381 towers or poles from 110-500 KV, thereby resulting in an insufficient power supply and appearing interruption of power supply in large area. The power utilization of 545 counties (districts) and 2,7060,000 users were affected simply in business scope of State Grid Corporation of China, among which the power supply in 80 counties (districts) was almost break-off completely. Consequently, the direct property loss was 10.45 billions CNY.
The extreme hostile weather, external force destruction, etc. have an important effect on power safety production and safety of lines and towers. Therefore, monitoring the operation status of the line and power grid fully is very important for enhancing the safety, reliability, stability, and economy of the power system.